ACUTE AND CHRONIC PHASES OF TOXOPLASMA-GONDII INFECTION IN MICE MODULATE THE HOST IMMUNE-RESPONSES

Murine antibody responses to soluble proteins are generally restricted to the immunoglobulin G1 (IgG1) isotype. When mice were infected with Toxoplasma gondii Beverley and concomitantly immunized with a soluble unrelated protein antigen, a modification in the isotypic distributio n of antibodies directed against this nonparasite antigen was observed , with a preferential production of IgG2a. Interestingly, when mice we re immunized with a soluble protein antigen during the chronic phase ( day 40) of infection with T. gondii Beverley, a similar modification i n the isotypic distribution of antiprotein antibodies was observed.